Welcome

Dr Andrea Banzatti - Postdoctoral Research Associate at LPL

Ph.D., 2013, ETH Zurich (Advisor: Prof. Michael R. Meyer)

My publications on ADS or on ADS beta , and my full CV

Main research interests and skills:

Planet formation tracers across the wavelength spectrum (from near- and mid-infrared to millimeter wavelengths) and disk evolutionary stages (from primordial, to transitional, to debris disks). Disk properties to understand the origins of exoplanet compositions. Re-processing of molecular gas (water, CO, and organic molecules) in planet-forming regions during variable accretion in young stars. Dust grain growth in disks, as linked to observable tracers of disk evolution and of the water snow line during planet formation. Development of novel tools for spectroscopy data analysis and interpretation; multi-component spectral fitting techniques for medium to high resolving powers (from R=600 of Spitzer-IRS, to R=100,000 of VLT-CRIRES).

NEWS:

The new ApJ paper on The depletion of water during dispersal of planet-forming disk regions is now published online.

Talks and discussions from the 2016 workshop "Linking Exoplanet and Disk Compositions" are now available on the STScI webcast archive .

In October 2016 I moved from Space Telescope Science Institute to the University of Arizona, Lunar & Planetary Laboratory.

Using the method proposed in Banzatti et al. 2015 , a paper on Nature presents the first ALMA image of the water snow line in a protoplanetary disk.

Links:

Project EOS: Earths in Other Solar Systems

My post on the STScI Science Blog: "Disk, gaps, and exoplanets - a journey on the wings of a dragonfly"

My STScI Public Lecture on Building New Worlds in Protoplanetary Disks

Simon Bruderer's essential conversion tools (Thank you Simon!)

Science highlights

THE PHYSICAL AND THERMO-CHEMICAL EVOLUTION OF PLANET-FORMING DISKS AT 0.01-10 AU

The figure shows the temperature-radius (T-R) diagram of carbon monoxide (CO) gas in protoplanetary disks. CO is a ubiquitous tracer of molecular gas in disks, and a sensitive thermometer of the radiation environment. The diagram above is constructed from spectroscopy surveys of rovibrational CO emission obtained with CRIRES at the Very Large Telescope, which currently provides the sharpest and most sensitive view of molecular gas in inner disks. The diagram unveils an empirical temperature profile for inner disks around solar-mass stars between 0.03 and 3 AU, by tracing the local warm dust color through infrared pumping. Between 2 and 25 AU, an inversion in the temperature profile reveals disks that have large depletions in their inner dust and gas radial structures, allowing ultraviolet pumping of CO emission at such large distances from the central stars. The T-R diagram of CO emission provides an empirical sequence of disk gap opening in protoplanetary disks, spanning the entire planet-formation region (~ 0.1-10 AU) and evolutionary stages from primordial to debris disks. In the figure above, the CO sequence is put into context of the Solar System planets and of the observed distribution of massive exoplanets that may migrate and open gaps in disks (with Msini > 0.5 Jupiter masses, from exoplanets.org).

Read here the scientific publication of this work, on the Astrophysical Journal: Banzatti & Pontoppidan 2015, ApJ, 809, 167

Read here a more poetic description on the STScI science blog: "Disk, gaps, and exoplanets - a journey on the wings of a dragonfly"

A follow-up paper describes the analysis of water and its depletion as molecular gaps form in inner disks: Banzatti et al. 2017, ApJ, 834, 152 . More is coming on the analysis of molecular gaps and holes in inner disks, including modeling work and synergies with inner disk dust tracers, stay tuned...

Imaging the WATER SNOW LINE from two ALMA continuum bands

The figure illustrates a proof-of-concept method proposed in Banzatti, Pinilla, et al. 2015 to image the water snow line in protoplanetary disks, through its signature imprinted in the dust continuum spectral index as observed at millimeter wavelengths from two ALMA continuum bands. We adopt a physical disk model that includes dust coagulation, fragmentation, drift, and a change in fragmentation velocities of a factor of 10 between dry silicates and icy grains as found by laboratory work. We find that the presence of a water snow line leads to a sharp discontinuity in the radial profile of the dust emission spectral index due to replenishment of small grains through fragmentation. The cartoon to the left illustrates the key components of this effect, while the model simulation to the right shows how ALMA would image the snow line by combining two continuum bands. We propose that ALMA continuum images of disks should be found to commonly show the water snow line, when the necessary spatial resolution is achieved.

This work is now available in ApJ Letters: Banzatti, Pinilla, et al. 2015, ApJL, 815, L15

A first detection of the water snow line using this method has been reported by Cieza et al. 2016 using ALMA: the paper is published on Nature

Monitoring the EFFECTS OF EPISODIC ACCRETION outbursts: UV photo-chemistry and inner disk draining

The figure shows a summary of observations and results obtained as part of monitoring studies of EX Lupi (the prototype of EXor variables) pre-, during, and post-outburst in the years 2005-2014. The lightcurve of EX Lupi is shown at the top of the figure: the strong accretion outburst in 2008 is visible in the 5 magnitude increase in the V band, while the data utilized in this work are marked with vertical lines. The Spitzer-IRS spectra were obtained before and during the ouburst, showing disappearance of organics and simultaneous increase in water and OH emission during outburst. This dataset provides first direct evidence that UV photo-chemistry (dissociation of molecules, e.g. water into OH) is triggered in inner disk surfaces during accretion flares. The increase in water emission is consistent with a larger amount of water vapor as released by icy bodies evaporated through a recession of the snow line at larger disk radii during outburst. The CRIRES data showed a strong decrease in water, OH and CO emission after outburst, and allowed to measure the amount (> 1 order of magnitude) and region (< 0.3 AU) of disk material drained during the outburst, which left the inner disk largely depleted of gas. Now the system is again in an "accumulation" phase (cartoon at the bottom), during which disk gas is piling up beyond the corotation radius until the next outburst will be triggered. Observations of EX Lupi give now the opportunity to study the timescales of organic chemistry in inner disks, through monitoring their infrared features while organics may re-form after UV photo-dissociation.

Read here the scientific publications of this study, on the Astrophysical Journal Letters: Banzatti et al. 2015, ApJL, 798, 16 , and on the Astrophysical Journal: Banzatti et al. 2012, ApJ, 745, 90

Exoplanets & Disks 2016

Linking Exoplanet and Disk Compositions - STScI workshop on September 12-14, 2016

This workshop will gather scientists working on the compositional characterization of planets and planet-forming regions in protoplanetary disks. Recent and upcoming advancements make it timely to have a round-table conversation among the several communities involved, to join forces in tackling our most compelling questions on the origins of exoplanet diversity. Do exoplanet compositions retain the imprint of large-scale disk processes? Do disks include compositional trends that imprint on planets? What do we learn in this context from observations of Solar System bodies? And what can we test with observations of disks and exoplanets in the near future? We intend to identify long-lasting and observable links between exoplanet and disk compositions, to help the community in shaping ongoing modeling efforts as well as the essential parameter space to cover with existing and upcoming observatories for exoplanet and disk characterization.

Infos:

Talks and discussions from the workshop are now available on the STScI webcast archive .

Publications & Plots

Contact

Current address:

University of Arizona
Lunar and Planetary Laboratory
1629 E University Blvd
Tucson, AZ 85721
USA

Email:

banzatti-AT-lpl.arizona.edu